Water defrost refrigerated showcase



June 5, 1956 D. H. GASTON WATER DEFROST REFRIGERATED SHOWCASE 3Sheets-Sheet 1 Filed March 24, 1952 .N 5 km H mm M mfifim N. 7 I y 4 mMv MfiM 2 Z June 5, 1956 D. H. GASTON 2,748,574

WATER DEFROST REFRIGERATED SHQWCASE Filed March 24, 1952 5 Sheets-Sheet2 flo/vALz) h. GA STON BY fir 6 8 H T7012 NEY$ June 5, 1956 D. H. GASTONWATER DEFROST REFRIGERATED SHOWCASE -melting'the frost accumulatedthereon.

United States Patent WATER DEFROST REFRIGERATED SHOWCASE Donald H.Gaston, Los Angeles, Calif., assignor to Weber Showcase & Fixture Co.,Inc., Los Angeles, cans, a corporation of California Application March24, 1952, Serial No. 278,246

Claims. (Cl. 62-895) This invention relates to an improved water defrostrefrigerated showcase.

It is an object of this invention to provide means-for periodicallydefrosting an open type refrigerated showcase.

It is a further object of this invention to provide water defrost meansfor a refrigerated showcase which is unaffected by varying waterpressures in the supply lines.

Still a further object of this invention is to provide water defrostmeans for a refrigerated showcase wherein the volume of water utilizedis readily controllable.

Still a further object of this invention is to provide means fordefrosting a refrigerated showcase which'insures a continuous supply ofwater to the defrosting device during a predetermined period of time.

Other objects and advantages of this invention will be readily apparentfrom the following description.

Inthe drawings:

Figure 1 is a perspective view with the showcase'in phantom of ashowcase embodying this invention;

Figure 2 is a side elevation partially in section, taken on line 2-2 ofFig. 1, of a showcase embodying this invention.

Figure 3 is a rear elevation partially in section, taken on line 33 Fig.2, of a showcase embodying this invention'.

Figure 4 is a schematic representation of an electric circuit useful inperforming certain features of the present invention.

Figure 4A is a simplified version of the circuit .illustrated in Figure4.

Figure 43 illustrates the relative times at which the switches shown inFigures 4 and 4A are operated;

Referring now to Figures 1, 2 and 3, an open-type refrigerated showcaseis illustrated having side walls Hand 14, a high rear wall 16, a lowfrontwall 18, and a-base 20, all of which are insulated and constructedin the usual-manner. Provided in the display caseis an open display bin22 which extends from side wall to side wall-but terminates short of thefront and rear wallsito form air passages 24 and 26. Blowers 28 arelocated beneath the display bin adjacent the refrigerating coils 30 sothat air is directed over the coils 30 and circulated through either oneof the air passages over the top of thezopen display bin and throughtheother air passage and isrecirculated in a manner well known to thoseskilled in the-art. As cooled refrigerant is circulated through coils 30considerable moisture condenses on thecoils necessitating defrosting ofthe coils. This is accomplished by water from tank 32 being releasedthrough pipe'34 "to the pipe 36'which is provided with a plurality ofspaced orifices 38 which sprays the water evenly over the coils Thewater and frost .drop onto the inclined base 20 between the coil supportbrackets 40 and 42 and out drain 44 which is .positioned atapproximately the lowest point in the base 20 which base may be formedto drain all the water to a low point as best seen in Figure 3.

Water flow from. the tank 32 to pipe 34 is controlled by rubber ballvalve46 which seats in a valve seat 48 formed in the upper extremity ofpipe 34. When the ball valve 46 is raised by means of solenoid 50 waterpasses from the tank 32 through pipe 34 out orifices 38 and over coils30 and out drain 44 defrosting the coils. When the solenoid 50 istie-energized the .ball 46. again seats on seat 48 terminating flow tothe coils.

It is of course desirable to terminate circulation of refrigerantthrough coils 30 and shut off blowers 28 during this defrost period.

Water is admitted from any suitable source through pipe 52 to a floatvalve 54 which valve is controlled by the position of ball 56. When theball is lowered it forces spring urgedplunger-58 down opening the floatvalve. When water fills the tank the ball rises and a spring closes thefloat valve and urgesplunger 58 upwardly.

If for some reason the float valve fails to function properly anoverflow tube 60 may be provided which terminates above the normal levelof water in the tank and at the other extremity in the pipe 34 below theball valve 46.

As previouslydescribed, when defrost commences the compressor motorcirculating refrigerant is stopped, the blowers are shut off and thesolenoid 50 is energized. This may be accomplished by thecircuitillustrated in Figure 4, which circuit may behoused in the control box51.

The circuit is energized by an alternating current source which hasopposite terminals thereof connected to the leads 101, 102. A clock 103has its terminals connected to such leads 101, 102,- and is constructedin conventional manner to operate the associated normally open switch103A andto maintain such switch 103A closed for a predetermined time,for example, for 5 minutes. The exact time at which the switch 103A isclosed may be adjusted, and since commercially available clocks are wellknown for this purpose, a detailed description of a particular one isnot given here.

Closure of the switch103A results in energization of the relay winding105 to close the normally open switch 105A and to simultaneously openthe normally closed switch 105B. Closure of switch 105A results inenergization of the cam motor 106 to cause rotation of its shaft. Thecam motor 106 serves to operate the associated switches106A, 106B and1060. For this purpose, the cam motor 106. has a cam (not shown) mountedon its output shaft for operating such switches 106A, 106B and 106C inthe time intervals discussed below and illustrated in connection withFigure 413. After the cam motor 106 has been energized fora relativelyshort period of time, its associated normally open switch 106A is closedto thereby seal the relay winding 105 to assure the continuedenergization vo-f relay winding 105 even though the switch 103A isallowed to subsequently assume its normally open position. Asamatter offact, the switch 103A, after a short period of time, .as illustrated inFigure 4B, is allowed to open.

Figure 4B shows a series .of hatched rectangles, each hatched rectangleservingto illustrate the time interval during which the associatedswitch is actuated from its normal condition. Thus, at time To, theclock switch 103A is actuated to closed position. Subsequently, at timeT1, the cam operated switches 106A, 106B and 106C are simultaneouslyactuated. Thereafter, at time T2, the switch 103A is allowed to openbut, of course, since the switch 106 is closed, relay winding 105continues to be energized.

Energization of relay winding 105, in addition to causing closure ofswitch 105A results in opening of the associated relay switch 105B tothereby de-energize the fan motor 107. The fan motor 107 remainsde-energized during the entire defrost cycle. Similarly, the cam motor106 is energized during the entire defrost cycle; and, the cam motorserves to de-energize itself since after the defrost cycle, the switch106A is allowed to open to thereby cause de-energization of relaywinding 105 and opening of the relay switch 105A. The normally closedcam operated switch 1063 is serially connected with the compressorcontrol circuit 108 so that while such switch 106B normally allows suchcompressor control circuit to be energized, such control circuit 108 isde-energized a fractional part of the defrost cycle, as represented bythe time interval T1T4. The other cam operated switch 106C, althoughactuated at the same time as the other switches 106A and 106B, remainsactuated for a shorter period of time than switch 106B. In other words,the switch 106C is actuated only during the time interval represented bythe time interval T1T3. The switch 106C, a normally open switch, servesto energize the water control solenoid 50 so that water flows during thetime interval T1-T3. During the time interval T3T4, the water is allowedto drain; and after time T4, the compressor is fully energized so thatit operates during a later fractional part of the defrost cycle, duringthe time interval T4-T5.

By these expedients, the compressor is shut otf during the period thatwater is introduced into the case and also during the following waterdrain period; and the compressor is allowed to start up and cool thecoil prior to ending the defrost cycle and prior to turning the fansback on.

If desired, the draining line 44 is provided with a normally opensolenoid operated valve 110, as shown in Figure 2. When used, thesolenoid valve 110 is connected electrically, as designated in Figure4A, with opposite terminals thereof connected to opposite terminals ofthe Water inlet solenoid 50; thereby both solenoids 50 and 110 areenergized simultaneously and de-energized simultaneously. By thisexpedient, instead of allowing approximately 40 gallons of water to gothrough the system and flush out into the drain the solenoid operatedvalve 110 shuts off the flow of water through the drain, therebyallowing the pan of the case to fill with water, thereby holding theheat of the water and using it. In such case instead of requiring 40gallons of water for defrost purposes, this amount may be reduced to 20gallons.

It is preferred that the pipe 34 running from the flush tank to the pipe36 project down the rear of the case and beneath the case and upwardlythrough the front wall to the pipe 36. This is desirable to avoid wateraccumur lating in the pipe and freezing therein during normal operationsof the showcase. When the pipe is conducted in this manner any waterwhich may collect outside and below the display case will not be subjectto suflicient reduced temperature to freeze the Water. It is sometimesdesirable to provide a bleeder tube 62 connecting with pipe 34 prior toits entry at the front of the showcase. Thus any water which accumulatesin the pipe 34 above the level of the bleeder tube drains into asuitable receptacle.

While what hereinbefore has been described as the preferred embodimentof this invention, it is readily apparent that many alterations andmodifications can be resorted to without departing from the scope ofthis invention and dependent claims.

I claim:

1. A water defrost refrigerated showcase comprising: an open displaybin, air circulating passages at the front and rear of said display bin,an air circulating passage beneath said display bin, a blower,refrigerating coils in said last mentioned passage through which coilsrefrigerant is circulated, and means in said last mentioned passage forspraying water over said refrigerating coils to defrost said coils, atank for storing water for said spraying means, a ball valve controllingflow from said tank, and a float valve controlling flow into Said tank.

2. A water defrost refrigerated show case comprising: an open displaybin, air circulating passages at the front and rear of said display bin,an air circulating passage beneath said display bin, a blower,refrigerating coils in said last mentioned passage through which coilsrefrigerant is circulated, and means in said last mentioned passage forspraying water over said refrigerating coils to defrost said coils, atank for storaging water for said spraying means, a ball valvecontrolling fiow from said tank, and a float valve controlling flow intosaid tank, and control means for opening and closing said ball valve fora predetermined period.

3. A water defrost refrigerated showcase comprising: an open displaybin, air circulating passages at the front and rear of said display bin,an air circulating passage beneath said display bin, a blower,refrigerating coils in said last mentioned passage through which coilsrefrigerant is circulated, and means in said last mentioned passage forspraying water over said refrigerating coils to defrost said coils, atank for storing water for said spraying means, a ball valve controllingflow from said tank, and a float valve controlling flow into said tank,control means for opening said ball valve, means for actuating saidcontrol means to open said ball valve for a predetermined period oftime, said last mentioned means shutting off said blower and terminatingflow of refrigerant through said coils when said ball valve is opened.

4. A water defrost refrigerated showcase comprising: an open displaybin, front and rear walls spaced from said display bin to form airpassages therebetween, a bottom Wall spaced from said display bin,refrigerating means between said bottom wall and said display bin, ablower circulating air over said refrigerating means up one of said airpassages over said display bin and back through the other of said airpassages to be recirculated, and water spraying means positioned abovesaid refrigerating coils, a drain pan beneath said refrigerating coils,and means for accumulating water sprayed over said coils in said pan fora predetermined time before draining said pan.

5. A water defrost refrigerated showcase comprising: an open displaybin, front and rear walls spaced from said display bin to form airpassages therebetween, a bottom wall spaced from said display bin,refrigerating means between said bottom wall and said display bin, ablower circulating air over said refrigerating means up one of said airpassages over said display bin and back through the other of said airpassages to be recirculated, and water spraying means positioned abovesaid refrigerating coils, a pan beneath said refrigerating coils, adrain from said pan, valve means controlling flow through said drain,and means closing said drain for a predetermined time thereby collectingwater sprayed over said refrigerating coils in said pan and utilizingheat given off by water so collected to defrost the refrigerating coils.

References Cited in the file of this patent UNITED STATES PATENTS970,807 Faget Sept. 20, 1910 1,626,255 Roth Apr. 26, 1927 2,056,087Andrews Sept. 29, 1936 2,323,511 Baker July 6, 1943 2,476,184 GoddardJuly 12, 1949 2,505,201 Peterson Apr. 25, 1950 2,524,568 Kritzer Oct. 3,1950 2,528,916 Shreve Nov. 7, 1950 2,571,192 Brill Oct. 16, 19512,626,401 Blair a- Jan. 27, 1953 2,649,695 Kohlstedt Aug. 25, 1953

